JPS63201088A - Controlled-vapor pressure type crystal pulling up device - Google Patents

Abstract

PURPOSE:To simplify the title controlled-vapor pressure type crystal pulling up device by hermetically sealing a highly dissociative component gas in a closed chamber formed by a crucible contg. a raw material melt and a heating wall integrated with the crucible, and pulling up the crystal of a high- dissociation pressure compd. in the chamber. CONSTITUTION:The closed chamber 29 is formed by the crucible 21 contg. the raw material melt 22 and provided with a main heating means 36, the heating wall 26, and a lid 33. The highly dissociative component gas, formed by heating and vaporizing a high-dissociation pressure component material 32 contained in a small hole 31 while controlling the pressure by a vapor pressure-controlling and heating means 40, is supplied into the closed chamber 29 and enclosed. In the closed chamber 29 under such conditions, a crystal 23 of the high-dissociation pressure compd. is pulled up from the raw material melt 22 by a lifting shaft 24 inserted through a seal plate 27 and a sealing means 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vapor pressure controlled method used when growing crystals of compound semiconductors containing components with a high pH 1ilit pressure, such as m-v group compounds such as GaAs. Involved in crystal pulling equipment.

[N key points of invention]

The present invention provides vapor pressure control that includes a crucible that neutralizes the raw material melt and a heating wall integrated with the crucible to confine high dissociation pressure component gases and constitute a closed chamber for pulling up crystals of the high dissociation pressure compound from the raw material melt. The present invention is a type crystal pulling device, which facilitates control of the pressure of a high dissociation pressure component gas and simplifies the manufacturing of the device.

[Conventional technology]

Conventionally, the horizontal Bridgman method (HB method) or the liquid confinement method (LEC method) has been used to grow crystals of compound semiconductors containing high dissociation pressure components, such as m-v group compounds such as GaAs, from their raw material melts. Can be mentioned.

Although the HB method has the advantage that the m-v group element composition can be made close to 1:1 because the vapor pressure can be easily controlled, the shape of the grown crystal is determined by the shape of the boat containing the raw material melt. A large amount of waste occurs when, for example, a generally used circular compound semiconductor wafer is taken out from the grown crystal.

In addition, when using the LEC method, the surface of the raw material melt is, for example, B
Covering with 2O3 suppresses the dissociation and evaporation of, for example, As under high dissociation pressure, but even with this method, there is a problem that a compositional deviation of the ■-■ group element occurs and the crystallinity decreases.

As a pulling method that avoids these problems and has the advantages of the above-mentioned methods, a pulling method using vapor pressure control (hereinafter abbreviated as VPCC) has been considered. However, a device that implements this VPCC method requires various requirements. The requirements are listed below: 1. In order to maintain the required internal pressure in a closed chamber with a high dissociation pressure group Ⅰ element, for example, As, a heated wall (hot wall) is heated to a temperature at which A3 does not deposit and adheres. ), and for example, in the case of A3, the temperature of this heating wall must be 617° C. or higher at 1 atm.

2. Steam pressure control requires, in part, salinity control means to determine the pressure.

3. Requires heating means and power source for controlling raw material melt and crystal growth.

4. Liquid sealing using THO 3 is generally used to seal the crystal pulling shaft, and a heating means and power source are required for this purpose.

5. Liquid sealing according to item 4 and tho 3 above for sealing the rotating shaft that rotatably supports the crucible of the raw material melt requires a heating means and its power source.

6. The material of the heating wall must be able to withstand high temperatures, be gas impermeable, and not corrode even in the vapor atmosphere of this high dissociation pressure component gas, such as the group Ⅰ element.

As described above, a device that implements the VPCC method must satisfy many requirements, and its structure is complicated.

FIG. 1 shows a cross-sectional view of the general structure of a conventional vapor pressure controlled crystal pulling apparatus that implements the above-mentioned VPCC method. In the figure, (1) contains a raw material melt, such as a GaAs melt (2). The crucible, (3) is the single crystal pulled from this raw material melt (2), (4 is its pulling axis, (5) is the crucible axis that moves the crucible (1) up and down and rotates, and (6) is the single crystal pulled from this raw material melt (2). A heating wall surrounding the crucible (1) and a pulling part for pulling the crystal (3) from the crucible, and a shaft (4) and (
5), each MiI 11 section is provided with a sealing means (8) containing a sealing liquid (7) such as 8203 for airtightly sealing it. Further, a vapor pressure control section (9) is provided in the upper part of the space surrounded by the heating wall (6), and a vapor pressure control heating means (10) such as an electric heater is sunk around the vapor pressure control section (9). Moreover, the heating wall (6) is heated to the required temperature and the lifting shaft (4) is sealed at the upper circumference of the heating wall (6). Heating hand Ifi (11) for melting the sealing liquid (7) of t (8), for example, is similarly provided with an energized heater and moves up and down around the crystal pulling part along with the up and down movement of the crucible (1). Main heating means (12
) For example, an electric heating heater may be installed in the same way, and a heating wall (
6) A sealing liquid (7) of a sealing means (8) for sealing the penetrating portion of the lower crucible shaft (5); a heating means (13) for dissolving, for example, B2O3; It will be done. These heating means (11) (12> (1
A heat insulating body (14) is arranged around the arrangement part 3), and a cooling jacket, for example, a water-cooled cooling jacket (15) is arranged outside of the heat insulating body (14).

Further, as this type of vapor pressure controlled crystal pulling apparatus, for example, Japanese Patent Application Laid-Open No. 60-255692, Japanese Patent Application Laid-Open No. 60-255692
Publication No.-251191, JP-A-60-226491
JP-A-60-251194 and JP-A-60-176995, all of which have a crucible (1 ) and the heating wall (6) are constructed separately, and sealing means for sealing the crystal pulling axis and the crucible axis are respectively disposed at the portions from which the crystal pulling axis and the crucible axis are derived. Both of them have problems such as relatively complicated structures and therefore complicated maintenance and handling.

(Problems to be Solved by the Invention) The present invention provides the above-mentioned vapor pressure controlled crystal pulling apparatus,
The aim is to simplify its structure, maintenance and handling.

Means for Solving Problem C) The present invention, as shown in FIG. 1, is a vapor pressure type crystal pulling apparatus that seals a high dissociation pressure component gas and pulls up crystals of a high dissociation pressure compound while controlling the pressure. In the raw material melt (2
2) and a heating wall (26) provided integrally therewith, the high dissociation pressure component gas is confined and the crystals of the high dissociation pressure compound (23) from the raw material melt (22) are sealed.
) constitutes a sealed chamber (29) for pulling up.

[Effect]

In the present invention, by integrating the crucible (21) and the heating wall (26), the structure can be simplified, and in particular, the part where the crucible shaft is led out from the closed chamber (29) can be omitted. By omitting the sealing means for leading out the shaft and, therefore, complicated structural parts such as sealing liquid storage, it is possible to simplify manufacturing and thereby simplify handling.

(Example) Further, with reference to FIG. 1, an example of a vapor pressure controlled crystal pulling apparatus according to the present invention will be described in detail.

In the present invention, a crucible (21) containing a raw material melt (22), such as a GaAs melt, is integrated with a heating wall (26).

The crucible (21) is provided with, for example, a plurality of (only one is shown in the figure) through holes (30) penetrating the bottom of the crucible (21) in its circumferential wall. A crucible shaft (25) having a pedestal (45) at its upper end for receiving the crucible shaft (21) is arranged below the bottom of the crucible (21). A small hole (31) is bored in the center of the crucible shaft (25) and communicates with the through hole (30) provided in the peripheral wall of the crucible (21). A high dissociation pressure component gas material (32) is accommodated. This high dissociation pressure component material (32) is accommodated in a narrow size (
31), whose upper end is the base (45) of the crucible shaft (25)
An annular projection (35^) is provided on the outer periphery of the upper surface of the base (45), and an annular projection (35^) that matches the annular projection (35^) is provided on the outer periphery of the bottom of the crucible (21). 3
5B), and the two are airtightly fitted together by means of mounting means (34) such as mounting screws. In this state, a small hole (31) was formed through the upper end of the wall of the crucible (21) through the gap (46) formed between the base (45) and the bottom of the crucible (21). It communicates with the through hole (30).

The heating wall (26) is formed in a cylindrical shape extending concentrically with the upper end of the crucible (21), and a lid (33) is attached to the upper end surface of the heating wall (26).
A closed space is formed by the pot (21) with a closed lid and the heating wall (26).

In addition, a crystal pulling shaft (24) is passed through the center of the lid (33), and a sealing liquid (such as 820 s) is applied at this penetrating portion.
A sealing means (28) is provided in which the opening (27) is housed, and is adapted to hermetically seal this penetration. (5
1) is an internal observation window provided on the lid (33) and sealed with a heat-resistant transparent body.

Then, the crucible (21) is heated between the crucible (21) and the heating wall (26), and thus the raw material melt (22) contained therein is heated to a desired temperature, and the crystal pulling part is heated to a predetermined temperature. A main heating device (36) for heating the heating wall (26) to a required temperature, that is, for example, an energizing heater having a required heating temperature distribution is arranged. Further, a heating means (37) for melting a sealing liquid (27) such as B2O3 is arranged on the outer periphery facing the sealing means (2 days).

In addition, a heating means (40) for controlling vapor pressure, such as a similar electric heater, is arranged around the part where the high dissociation pressure component material (32) is placed in the small hole (31) formed in the crucible shaft (25). . (41) indicates a heat detection means for controlling the heating means (40) by detecting the heating temperature of the high dissociation pressure component material with a heat detection element such as a thermocouple. And each heating means (36)
(37) A heat insulator (44) is placed outside the outer periphery of (40), and a cooling jacket (5
5) Place. (50) is a cooling jacket (5
5) shows an observation window to which the transparent plate formed in 5) is sealed.

The crucible (21), the heating wall (26), the crucible shaft (25), etc. are made of carbon material, and viroretain is applied to the surfaces that come into contact with the raw material melt (22) or the highly dissociated component material or its gas. It can be coated with a heat-resistant surface agent such as kusuboron nitride.

In such a configuration, the main heating means (36) melts the raw material melt (22) in the crucible (21), and brings this and the part where crystal pulling is performed to a solidus temperature, and the heating means (36)
40), the high dissociation pressure component material (3
2) The amount of evaporation is controlled, and through this the evaporation amount of
), the air gap (46), and the closed chamber (2) through the through hole (30).
9), a gas atmosphere of 1 atm at 617° C., for example, is maintained, and the heating wall (26) is heated to avoid adhesion of a highly dissociated gas such as As gas, and the inside of the sealed chamber (29) is maintained at a required vapor pressure of 1 atm, for example. Heat to 617°C and hold at . In this state, while rotating the pulling shaft (24), crystal growth is performed from the raw material melt (22) from the single crystal provided at the tip thereof.

At this time, the crucible shaft (25) is rotated, for example, in the opposite direction to the pulling shaft (24), so that the liquid level of the raw material melt (22) in the crucible (21), which decreases as the crystal is pulled, is at a predetermined position. It is made to move upward as it is.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, the crucible (21) and the heating wall (26) are integrally configured, thereby creating a seal containing a sealing liquid for airtightly sealing the crucible shaft (25). Since the provision of a sealing means can be avoided, the heating means for melting the sealing liquid and the power supply thereof can be omitted together with the sealing means, and the structure can be simplified and the sealed chamber ( In 29), when the high dissociation pressure component material arrangement part, that is, the vapor pressure control part is provided in the crucible shaft (25) below the sealed chamber, the internal volume of the sealed chamber can be further reduced, so the vapor pressure control is It has many industrial benefits, such as being able to pull the crystal more accurately and with stable quality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of a vapor pressure controlled crystal pulling apparatus according to the present invention, and FIG. 2 is a sectional view of a conventional apparatus. (21) Crucible, (22) raw material melt, (24) pulling shaft, (25) crucible shaft, (26) heating wall, (27
) is the sealing liquid, (28) is the sealing means, (40) is the heating means for vapor pressure control, (36) is the main heating means, (37) is the heating means, (30) is the through hole, (31) (32) is a high dissociation pressure component material.

Claims (1)

[Scope of Claim] A vapor pressure controlled crystal pulling device for pulling crystals of a high dissociation pressure compound while sealing a high dissociation pressure component gas and controlling the pressure thereof, comprising: a crucible containing a raw material melt; A vapor pressure controlled crystal pulling apparatus, characterized in that a sealed chamber is configured by an integrated heating wall to confine the high dissociation pressure component gas and pull up crystals of the high dissociation pressure compound from the raw material melt.